use integer division for `range()` parameter

Status Job ID Name Coverage
  Build
failed #9172
build:2.7

failed #9173
build:3

 
  Test
skipped #9175
allowed to fail
lint:2.7
skipped #9178
allowed to fail
lint:3
skipped #9174
pyflakes:2.7
skipped #9177
pyflakes:3
skipped #9176
unittests:2.7
skipped #9179
unittests:3
 
  Deploy
skipped #9180
doc:2.7
skipped #9181
doc:3
 
Name Stage Failure
failed
build:3 Build There is an unknown failure, please try again
No job log
failed
build:2.7 Build There is an unknown failure, please try again
No job log